Three tier architacture PL, BLL, DAL RRS feed

  • Question

  • User1435703709 posted

    I am going to write an 03 tier application using aps.net. I wanted to have sound concepts of all these layers. Plz reffer me any site/toturial that have concepts and a working sample as well.


    I have alrady worked on one such application, but I am still confused whether my approach is right or wrong 

    Wednesday, December 1, 2010 4:53 AM


  • User-952121411 posted

    I have alrady worked on one such application, but I am still confused whether my approach is right or wrong 


    Typically in a nutshell the DAL will extract the data and package it up, the BLL will manipulate the data based on business needs and potentially create business objects based on the logical model and not necessarily the one of the physical database structure, and the UI will consume and bind the data.  Of course there is a lot more going on than just these parts, but these are the high points.  The BLL specifically isolates the logic of the application and should be independent of the UI and database technologies. This will allow you to change the way the app communicates to the database or binds to the UI without effecting the primary logic of the application.  The BLL acts as the intermediary for communication between the (2) layers. 

    Below are (2) decent tutorials (with code examples in C# or VB.NET) written on creating a BLL and a DAL.  Take a look at them, and after understanding the purpose better, then apply that to your individual application.

    Creating a Business Logic Layer:


    Creating a Data Access Layer:


    Here are some other decent tutorials on a 3 layer logical design:

    Building an N-Tier Application in .NET:


    Building Layered Web Applications with Microsoft ASP.NET:


    ...and a great reference for general architecture:

    Microsoft Application Architecture Guide:


    Down the road when you have a sound understanding of layering applications, I recommend the following book by Scott Millett named Professional ASP.NET Design Patterns:


    Hope this helps! Smile


    • Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM
    Wednesday, December 1, 2010 9:45 AM

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